Watching gas prices? Insurance rates are even wilder

While most vehicle owners are used to seeing fluctuating gas prices—and trying to find ways to offset them—they may need to pay closer attention to ever-changing insurance prices.

According to a report by insuranceQuotes.com, which compared monthly premiums in all 50 states and Washington, D.C., insurance rates can vary by nearly 50 percent depending upon the month and the state.

Last year Hawaii saw a 47.9 percent price difference between its cheapest month, December, and its most expensive month, March.

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Wyoming (39.7 percent), Washington, D.C. (35.3 percent) and Maryland (34.8 percent) were next in line with the largest variance in rates. Conversely, South Dakota had the smallest difference at 1.9 percent, followed by Arkansas, Utah, Iowa and Kansas, which were all below 6 percent.

Complicating the issue is that there is no rhyme or reason to why—or even when—the rates are so disparate. The national median cost of a new full-coverage auto policy for a 35-year-old single male driver with a $500 deductible and a clean driving record was 7.5 percent cheaper in December than in March, according to the website.

"What's most interesting is that there's no discernible pattern to detect here," said Mike Barry, spokesman for the nonprofit Insurance Information Institute, in a released statement.

In the aforementioned case of Hawaii, it was nearly 48 percent cheaper in December than it was in March. December is often the least expensive month for insurance because new regulations or laws that could raise prices often go into effect at the beginning of the year.

That said, December was the most expensive month in 11 states, the study revealed.

"It appears as though the trend lines are all over the place, which doesn't really lend itself to a clear-cut reason or hypothesis for why that's the case," Barry said.

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While December was most often the cheapest month, March was typically the most expensive across the U.S. It took top honors in Washington D.C., and 15 states, ranging from Alabama to Wisconsin.

Combating the wide range of rates to ensure the best pricing can be tough, and it requires consumers to be extremely savvy about insurance trends, said Eli Lehrer, president of nonprofit research group R Street Institute.

Knowing whether a certain state is strict on how to implement increased rates is extremely helpful, he said. States with minimal rate regulation may allow insurers to change their rates whenever and however they please; however, in states with stricter rate regulation, insurers need to go through lengthy filing and approval processes to get rates changed.

"All of this illustrates why it's so important for consumers to regularly shop for car insurance," said Laura Adams, senior insurance analyst for InsuranceQuotes.com, who recommends getting at least three different quotes before buying insurance..